title: Enzymatic cleavage of the epsilon-peptide bond in alpha- and epsilon-substituted glycyl- and phenylalanyl-lysine peptides.
abstract: Lysine peptides, X-Lys-OH (Formula: see text) were synthesized, following classic or non-classic routes. Some bacterial and mammalian enzymes, endo- and exo-peptide hydrolases of the enzyme nomenclature type EC 3.4., were tested for their ability to split the epsilon-peptide bond in the above substrates. Kinetic constants (Km,kcat) were evaluated with leucine aminopeptidase from hog kidney and eye lens with aminopeptidase I from yeast. Aminopeptidase M (hog pancreas) and hog intestinal aminopeptidase were additionally examined for their Ki values with the above substrates in comparison to the classic protease substrate leucine p-nitroanilide. Especially the intestinal mucosa hydrolases are shown to be efficient in cleaving epsilon-peptide bonds.
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D010450:Endopeptidases / Q000378:metabolism; D005998:Glycine; D007668:Kidney / Q000201:enzymology; D007700:Kinetics; D007908:Lens, Crystalline / Q000201:enzymology; D007931:Leucyl Aminopeptidase / Q000378:metabolism; D008239:Lysine; D009842:Oligopeptides / Q000138:chemical synthesis*; D010447:Peptide Hydrolases / Q000378:metabolism*; D010649:Phenylalanine; D012441:Saccharomyces cerevisiae / Q000201:enzymology; D013329:Structure-Activity Relationship; D013379:Substrate Specificity; D013552:Swine
chemical_list: D009842:Oligopeptides; D010649:Phenylalanine; D010450:Endopeptidases; D010447:Peptide Hydrolases; D007931:Leucyl Aminopeptidase; D008239:Lysine; D005998:Glycine